• Amaranth;
  • chemical composition;
  • amino acid content;
  • protein quality


A set of 14 selections of four amaranth species were studied. Six yielded over 10 kg 36 m−2, and three below 5 kg 36 m−2. Grain size varied from 1.55 to 2.14 mm, and seed weight from 0.46 to 1.18 mg seed−1. There was no relationship between seed weight and yield. Protein content varied from 12.5 to 16.0%, while fat varied from 7.7 to 12.8%. The content of P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn was similar among all selections. Trace amounts of C14 fatty acids were found, while C16 acids varied from 16.83 to 23.83% of the oil. The C18:0 fatty acids varied from 1.86 to 4.11%, the C18:1 from 20.29 to 35.46%, while the C18:2 fatty acids varied from 38.25 to 57.86%. Lysine varied from 0.73 to 0.84%, with tryptophan values ranging from 0.18 to 0.28%. Seeds from all selections were processed by hot-water soaking for 20 min followed by drum-drying, for protein quality evaluation.

The three A. caudatus had an average protein efficiency ratio (PER) of 2.45; A. hybridus a PER of 2.34; A. cruentus 2.36 and A. hypo-chondriacus 2.33. Differences were not statistically different. Light and dark coloured seeds had the same average value of 2.36, the study showed important genetic differences in chemical composition.